Defect Prediction: Microporosity in Castings
Cast metal parts are sometimes unusable because they have large internal gas pockets, or porosity, that develops when the metal shrinks during solidification. Most large-scale porosity can be eliminated by a careful design of the casting mold to keep extra liquid metal in special regions for feeding the shrinkage. When metal can flow to compensate for shrinkage, porosity usually does not occur.
Another type of porosity is referred to as micro-porosity because it usually appears as a distribution of small bubbles whose total volume fraction is typically on the order of 1% or less. Having a means of predicting the location and magnitude of micro-porosity is therefore of considerable interest. FLOW-3D Cast's microporosity model has been developed for this purpose.